Organic layer thickness: Wickersham fire sites (1971 - 2004)

In June of 1971, the Wickersham fire burned 6313 ha in an open black spruce forest underlain with permafrost and provided an opportunity to study fire and fireline effects on the rate and patterns of permafrost, soil, and vegetation recovery. When wildfire burns through a northern black spruce forest the degree of soil organic layer consumption greatly influences the post-fire community characteristics. The construction of firelines with heavy machinery involves the complete removal of vegetation and the soil organic layer down to mineral soil and likewise affects the community characteristics after fire and fire suppression. Reduction in organic layer thickness and the subsequent loss of thermal insulation has been shown to cause increased soil temperatures and increased depth of thaw of the active layer. This long-term study is a comparison between the organic layer thickness on firelines, burned and unburned open black spruce forests underlain by ice rich permafrost.